The Q&A session has become a staple for almost any subject you will illuminate with a PowerPoint presentation. Oftentimes, this is a warmly welcomed opportunity for the presenter to clear up any points where the audience might be a bit fuzzy while going into more detail where audience members are interested.
However, as we all know or will eventually find out, presentations don’t always go exactly how we want them to, and sometimes we might face some tricky questions that catch us a little off guard, or intentionally antagonistic questions meant to incite an argument.
As the presenter–the person at the front of the room–you, by default, become the situation’s moderator. It’s up to you to keep the order in the room and the conversation civil and on topic. Most importantly, no matter how hard it may sometimes be, you should always strive to be the most mature, level-headed person in the room when you have the audience’s attention.
Stay on Topic
First off, don’t let audience questions derail your presentation. If appropriate for the topic and allotted time, set aside 5 to 15 minutes at the end of your presentation for a Q&A session. If audience members chime in during your presentation, politely ask them to wait until the end of your presentation.
If your audience refuses to listen to reason and grows unruly, we address that here.
Don’t Lose Sight of Your Topic
There may be a million other things you and your audience want to discuss, and they will likely make that apparent when given the opportunity to ask questions, but remember, you’re the one tasked with controlling the flow of the conversation.
Whenever engaging with an audience member, always be working the conversation (as naturally as possible) back toward the main point of your presentation. This way, you’re not wasting the time you’ve allotted to conveying your message.
ALWAYS take the high ground
Similarly, even if an audience member really lobs one over the plate for you, don’t embarrass them for asking a stupid question. This may sound like your elementary school guidance counselor here, but although you may get a few laughs, anyone to be taken seriously will see your bullying as a sign of immaturity.
Take a deep breath before answering each question.
It’s common knowledge that our talking pace speeds up significantly when our adrenaline starts flowing, which happens often when we’re speaking in front of a crowd and our nerves are running high. 
Because of this, it’s easy for us to begin rambling when asked to speak off the cuff answering questions, so when you’re asked a question, even if it seems as simple as salt, pause, take a deep breath, and allow yourself a brief moment to formulate your response. You’ll find that this short pause will make your responses much more natural and articulate.
References:
“Keith Alexander Can Teach Us About Presenting to a Crowd.” SlideGenius. July 31, 2013.